This proposal is designed to establish a multidisciplinary, multiinstitutional effort to develop a gene therapy approach for the treatment of pediatric AIDS. The development of gene transfer techniques for inserting the gene for Rev, a transdominant negative inhibitor of HIV, into T and hematopoietic cells will serve as the model for this research. There are three major reasons to pursue these investigations. Although studies are progressing, there are currently no effective treatments for pediatric AIDS. Because the pathophysiology of AIDS in children differs from adults, it is unknown whether approaches which my be successful in adults will apply to children. Second, a subset of children with AIDS appears to have thymic function not found in adults, and provides a better model to evaluate the potential for hematopoietic cell reconstitution in this disease. Third, these studies will provide a paradigm for development of other HIV protective genes for gene therapy. The program will be comprised of three projects and one scientific support core. Dr. Nabel, together with Dr. Diane Wara, will evaluate the ability of peripheral blood T cells to persist in pediatric cases, comparing the role of Rev M10 and a control frameshift mutation similar to the studies proposed in adults. In addition, this project will begin to develop methods for nonviral gene delivery which will be used to develop vectors for delivery into hematopoietic stem cells. This group will work collaboratively to develop effective hematopoietic gene transfer for the treatment of the pediatric disease. These techniques will be evaluated in preclinical animal models to continue to optimize gene expression. In newer approaches, multiple genes will be targeted to optimize the efficacy of this treatment. Dr. Donald Kohn will develop a human gene therapy protocol to perform gene transfer in hematopoietic cells. Hematopoietic progenitor cells will be isolated from these cells and transduced with HIV protective vectors derived from Rev M10. Engraftment and survival of transduced cells will be monitored in these patients. This work will be performed in collaboration with Dr. Nabel together with Dr. Diane Wara, a co-investigator on both projects, to implement these protocols in children. Finally, the development of effective vectors will be performed with particular emphasis on targeting within cells of hematopoietic lineage. Dr. Daniel Littman of UCSF has pioneered the studies of the regulation of genes in the CD4+ lineage during development. His knowledge and expertise in CD4 gene expression will complement efforts to express HIV protective genes by optimizing the design of vectors for T and hematopoietic cell gene transfer. Taken together, these studies should provide the initial inroad to developing therapies for pediatric AIDS. These studies will serve as a paradigm for development of future therapies for pediatric AIDS and also provide insight into the pathogenesis of this disease in children.